1. Field of the Invention
The present invention relates generally to a packet data service network in a mobile radio communication network. In particular, the present invention relates to a packet data service network for a mobile station and a method of operating a packet data service using the packet data service network.
2. Background of the Related Art
In order to provide a packet data service in a mobile radio communication network based on IS-95 series a protocol function should be first provided to each network element which constitutes the mobile radio communication network as shown in FIG. 1. Specifically, a radio link protocol (RLP) of a radio section, a packet transmission link of an infrastructure section, and a frame relay link of a section between an interworking function device (IWF) and a base station controller/mobile switching center are respectively provided as a lower layer relay for transferring point-to-point protocol (PPP) link data between a mobile station (MS) and the IWF, while an Internet protocol (IP) network layer is provided as an upper layer of the PPP link.
A packet service procedure as shown in FIG. 2 should be performed to provide an Internet packet service to a certain mobile station (MS) using the above-described protocols.
Referring to FIG. 2, at step al, a mobile station (MS) is identified by and connected to a radio access network (RAN). At this time, dedicated resources between the MS and the RAN and between RAN and the IWF are adjusted.
At step b1, a PPP link between the MS and the IWF is determined using PPP LCP.
At step c1, the MS instructs the IWF to determine a permanent home address using PPP IPCP.
At step d1, the IWF/FA transmits an agent advertisement message and a care of address (COA) of an external agent to the MS using a mobile IP (MIP). At this time, the MS transmits an agent solicitation message to a foreign agent (FA), or responds to the FA with its agent advertisement reply.
At step e1, the MS determines whether the COA of the external agent is new or not. If the COA is new, the MS sends a registration request message to the FA to initialize a mobile IP registration. At this time, such a registration request message includes the home address of the MS, the home agent (HA) address, the address of the FA, and information on an identification extension between the MS and the HA.
At step f1, the FA sends an identification request message to the HA.
At step g1, the HA confirms the identification extension between MS and HA when FA receives the registration request message. At this time, if the identification of the MS is completed, the HA includes the home address of the MS in the COA of the FA and sends an identification reply to the FA. If the identification of the MS fails, or the HA rejects the registration request for a certain reason, the HA transfers the registration reply message to the FA, which indicates the reason of rejection.
At step h1, if the registration reply indicates that the HA accepts the registration request, the FA adds the home address of the MS and the registration lifetime to an FA visitor list, and then sends the registration reply to the MS.
At step i1, if the mobile IP registration is successfully performed, the MS may send the packets to the Internet to transmit the packets to a destination. The packets of the originating MS are sent to the IWF through the PPP link.
At step j1, the FA may route the packets of the terminating MS to the Internet, or send the packets directly to the HA.
At step k1, the packets of the terminal MS are routed to the HA.
At step l1, the HA sends the packets of the terminating MS directly to FA.
At step m1, the FA removes a tunnel overhead, and sends the packets of the terminating MS to the MS through the PPP link.
Specifically, as shown in FIG. 2, the mobile station is allocated with the Internet IP address to have the Internet packet service. This IP address is allocated as a temporary address or care of address (COA) during the set-up of the PPP link by the IWF, which matches the communication protocol so that the MS is connected to the existing wired network.
The IP address used by the MS is always related to IWF, and thus if the connection between the MS and the IWF, which is connected to the PPP link is cut off, the software of the upper layer should be directed to use a new IP address.
Accordingly, in order for the MS to perform a seamless Internet packet data communication, the mobile IP function of supporting the mobility of the IP address should allow for the continuous use of the IP address even though the MS deviates from the service area of the IWF. For the effective support of the mobility of the IP address, the area of the radio base station is divided into packet zones, and each specified IWF provides the service for each specified packet zone. At this time, the base station provides a lower function that the base station broadcasts a packet zone identifier as a system message so that the MS can identify its packet zone.
For instance, the MS, which is served with the mobile IP service by the mobile client software, receives the packet zone related information broadcasted from the system, and compares the information with a packet zone identifier stored therein.
If the two packet zone identifiers are different from each other as a result of comparison, the MS deviates from the IWF area to which the MS has connected, connects with a new IWF, and then sends the solicitation message to the IWF connected to the FA. The MS receives the FA advertisement information provided by the IWF as a reply message, and performs the mobile IP registration if the message indicates a new FA.
As a result, the mobile IP terminal can perform the Internet packet service continuously with its own IP address.
However, whenever the MS moves from a first packet zone to another packet zone to effect the mobile IP registration, it takes a lot of time to set up a new PPP link.
Also, since the MS should pass the FA solicitation procedure, the FA advertisement procedure, and the mobile IP registration procedure, a seamless handoff of the MS cannot be actually achieved. Accordingly, the MS may lose many packets that it has from the time when the MS moves to another packet zone to the time when the MS completes a new mobile IP registration.
Also, if a simple IP terminal having no mobile client software changes its packet zone, the currently used IP can no longer be used, and the upper application service layer should be completely restarted.
The above references are incorporated by reference herein where appropriate for appropriate teachings of additional or alternative details, features and/or technical background.
An object of the invention is to solve at least the above problems and/or disadvantages and to provide at least the advantages described hereinafter.
An object of the present invention is to provide a packet data service network in a mobile radio communication network and a method of operating a packet data service that substantially obviates one or more of the problems caused by the disadvantages of the related art.
Another object of the present invention is to provide a packet data service network in a mobile radio communication network and a method of operating a packet data service using the packet data service network which can maintain the PPP link of a mobile station and an interworking function device (SIWF) based on the relationship between an interworking function device (AIWF) for performing a relay link connection for connecting the mobile station and the interworking function device in a new area and the interworking function device (SIWF) which maintains the PPP link before the movement of MS in case that the mobile station deviates from a determined area while the mobile station is being served with the packet data service in the environment of a mobile radio communication network of cellular/PCS/IMT-2000.
Another object of the present invention is to provide a protocol operating method for performing a packet data service in a mobile radio communication network which can perform the mobile packet data service using a PPP link determined before the movement of a mobile station and a protocol of an upper layer of the PPP layer without the redetermination of a new PPP link and protocol of the PPP layer of the PPP layer if the mobile station deviates from a determined area while the mobile station is being served with the packet data service in the determined area.
Another object of the present invention is to provide a packet data service network in a mobile radio communication network which can provide the shortest access time by maintaining the initially determined link path between a mobile terminal and a base station controller or a mobile switching center when the mobile terminal deviates from a determined area while the mobile terminal is being served with the packet data service in the environment of the mobile radio communication network of cellular/PCS/IMT-2000, or the registration of a new location of the mobile terminal is not supported when the mobile terminal moves, or even in the environment of the mobile radio communication network based on IS-95A and IS-95B which is currently providing a commercial service.
To achieve at least these objects in whole or in parts and in accordance with the purpose of the present invention, as embodied and broadly described, the packet data service system in a mobile radio communication network comprises a packet router for providing originating or terminating traffic paths for a plurality of mobile stations and managing particulars of an event whenever the event is produced in the mobile stations, and an interworking function device for controlling the packet router to interwork with another network, wherein if a certain mobile station among the plurality of mobile stations deviates from a predetermined service area of the interworking function device while the mobile station is being served with a packet data service interworking with the another network, the packet router continuously maintains a point-to-point (PPP) link initially determined between the mobile station and the interworking function device in accordance with the managed particulars of the event.
In another embodiment of the present invention, there is provided a method of operating a packet data service in a mobile radio communication network comprising the steps of setting up a point-to-point (PPP) link between a mobile station and an interworking function device for interworking packet paths between the mobile station and another network in accordance with the packet data service required by the mobile station, managing particulars of an event using at least one information table in a packet router for routing the PPP link whenever the event is created by the mobile station, and continuously maintaining the PPP link initially determined or changing a relay path between the mobile station and the packet router using the managed particulars of the event in accordance with a cause of the event in the packet router if the event is created in a state that the mobile station deviates from a predetermined area.
In still another embodiment of the present invention, there is provided a method of operating a protocol communication in a mobile radio communication network comprising the steps of connecting relay links between a certain mobile station and a packet router and between the packet router and an interworking function device if the mobile station requests a packet data service, determining a point-to-point (PPP) link between the mobile station and the packet router through the link layer, performing an Internet packet data service in the mobile station using an Internet protocol (IP) address which indicates a permanent home address for the interworking function device, and maintaining the PPP link initially determined between the mobile station and the packet router if the mobile station which is being served with the packet data service still requires the packet data service even when the mobile station deviates from a predetermined unit area.
Additional advantages, objects, and features of the invention will be set forth in part in the description which follows and in part will become apparent to those having ordinary skill in the art upon examination of the following or may be learned from practice of the invention. The objects and advantages of the invention may be realized and attained as particularly pointed out in the appended claims.